JP2008276674A - Electronic computer capable of specifying execution time of task, and program for electronic computer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely specify an execution time of a task, even when the execution time of the task is very short, and to prevent an error from being generated in calculation of the execution time by other processing, in a technique for specifying the execution time of the task. <P>SOLUTION: The task assigned preliminarily is collated with the task to start an execution, a time when started is recorded when starting the execution task, when those are consistent each other, and a difference between a time when finished and the time when started is recorded as the execution time, when finishing the execution task. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electronic computing device that can switch a task to be executed by a CPU from among a plurality of tasks and that can specify an execution time of the task, and a program for the electronic computing device.

  Conventionally, various techniques for specifying task execution time in a CPU that switches a target task to be executed from among a plurality of tasks are known. As a method for specifying the task execution time, for example, a process of setting a predetermined flag in the RAM at the start of task execution and setting the flag to 0 at the end of task execution is repeated each time the task is executed, There is a method of periodically checking the change of the flag with a RAM monitor which is an external device. By using such a method, the task execution rate of the CPU, that is, the usage rate of the CPU can be specified from the ratio of the period in which the RAM is 1 in a certain period.

Further, methods for specifying the task execution time include those described in Patent Documents 1 and 2. In this method, the CPU executes an idle task at a time when a normal task is not executed, and periodically increases the counter value in the idle task. As a result, the ratio of the time during which the normal task is not executed in the period can be calculated from the increment of the counter within a certain period. The ratio can be calculated.
JP-A-5-40651 Japanese Patent No. 3376096

  However, in the method using the RAM monitor as described above, if the time from the start of execution of the task to the end of execution becomes shorter than the check interval of the RAM monitor, it cannot be detected that the task has been executed, and as a result The calculation result of the task execution time will be inaccurate.

  Further, in the method of increasing the counter value during the idle task, if other processing (for example, storage medium diagnosis processing) is performed during the idle task, the execution timing of the processing for increasing the counter value is affected by the processing, As a result, the increment rate of the counter value may not be constant. If the increment rate of the counter value is not constant, the calculation result of the task execution time becomes inaccurate.

  In view of the above points, the present invention is a technology for specifying a task execution time in a CPU that switches a target task to be executed from among a plurality of tasks. Even when the task execution time is very short, the task is reliably executed. The purpose is to allow the time to be specified, and to prevent the execution time from being distorted by other processes in the above-described manner.

  In order to achieve the above object, a first feature of the present invention relates to an electronic computer that includes a storage medium and a CPU and switches a task to be executed by the CPU from a plurality of tasks recorded in the storage medium. Is. In the first feature of the present invention, when the CPU starts execution of one of a plurality of tasks (hereinafter referred to as an execution task), whether or not the execution task is a designated task recorded in the storage medium. When the execution result of the execution task is started, the time at the start is recorded in the storage medium as the execution start time of the execution task. Further, at the end of execution of the execution task, the difference between the end time and the execution start time of the execution task recorded in the storage medium is recorded in the storage medium as the execution time of the execution task.

  In this way, a task specified in advance and a task to start execution are collated, and when they match, the difference between the start time and end time of the execution task is recorded as an execution time. The execution time of the task can be specified. By using such a method, even when the task execution time is very short, the execution time can be reliably specified, and the execution can be performed by other processes with the above-described mechanism. There is no error in the calculation of time.

  The second feature of the present invention is that a storage medium and a CPU are provided, and a plurality of first group tasks belonging to the first group and a plurality of second groups belonging to the second group are recorded on the storage medium. The present invention relates to an electronic computing device that switches a task to be executed by a CPU from among tasks. The CPU always executes one of the second group tasks when none of the first group tasks are executed.

  Further, the CPU executes the execution time of the second group task to be executed (hereinafter referred to as an execution task) in the execution of the second group task within a predetermined measurement period. The task execution start time is recorded on the storage medium, and at the end of execution of the execution task, the difference between the end time and the execution start time of the execution task recorded on the storage medium is Calculated as task execution time. Further, the CPU records the result of subtracting the total execution time of the execution tasks calculated within the measurement period from the measurement period as the execution times of the plurality of first group tasks in the storage medium.

  As described above, the tasks to be executed by the CPU are divided into the first group and the second group, and the task of the second group is always performed while the task of the first group is not executed. When a task is being executed, the execution time is measured for each task belonging to the second group within a certain measurement period, and the value obtained by subtracting the sum of the measurement results from the measurement period is It can be specified as the execution time of one group task.

  For each second group task, the execution time of the task can be specified by specifying the difference between the start time and the end time of the execution task as the execution time. By using such a method, even if the task execution time is very short, the execution time can be specified reliably, and the execution time of the task can be determined by other processes with the above-described mechanism. There will be no error in the calculation.

  Further, in the second feature of the present invention, each of the tasks belonging to the second group is a platform task for directly controlling the hardware and operating system of the electronic computing device, and belongs to the first group. Each may be an application task that uses the hardware and operating system of the electronic computing device via a platform task. In this way, it is possible to meet the general need to know the CPU usage rate by the application task.

  Further, the function of recording the result of subtracting the total execution time of execution tasks calculated within the measurement period from the measurement period in the storage medium as the execution time of the application task may be realized as a platform task. In this way, the application task execution time calculation function can be designed as part of the platform, so the application task designer creates a program for calculating the application task execution time. There is no need.

  The first and second features of the present invention can also be realized as a program.

  Hereinafter, an embodiment of the present invention will be described. FIG. 1 shows the configuration of the ECU 1 and the connection relationship with the RAM monitor 2 according to this embodiment. The ECU 1 is an electronic control device that is mounted on a vehicle and controls the behavior of the vehicle. For example, the ECU 1 may be an engine ECU.

  The ECU 1 includes a timer 10, a RAM 11, a ROM 12, a CPU 13, and the like. The timer 10 measures the passage of time. The CPU 13 reads the program from the ROM 12 and executes it, and performs various calculations using the RAM 11 as a work area during the execution. Further, the CPU 13 may acquire information in the vehicle from a sensor (not shown) (for example, a vehicle speed sensor or an accelerator opening sensor) during the calculation, or an actuator (for example, an injector or an antilock brake device) (not shown). You may come to control. The RAM monitor 2 is a device that can read the stored contents of the RAM 11 when connected to the ECU 1 when necessary.

  Here, a program executed by the CPU 13 will be described. The programs recorded in the ROM 12 include a program for a real-time operating system (hereinafter referred to as RTOS), a platform program, and an application program. FIG. 2 conceptually shows the hierarchical structure of the application 31, platform 32, and RTOS 33 in relation to the hardware 34. The RTOS 33 is a system that directly controls the hardware (RAM, ROM, I / O not shown) 34 of the ECU 1. As the RTOS 33, for example, an OSEK (registered trademark) specification may be used. The platform 32 is a system that directly controls the hardware 34 and the RTOS 33.

  The application 31 is a system for realizing various functions of the ECU 1 (for example, engine control, auto-cruise control, lane keep control, etc.). For this purpose, the hardware 34 and the RTOS 33 are used via the platform 32. To do. The existence of such a hierarchical structure eliminates the need for an application to directly use the functions of the RTOS 33 and the hardware 34. Therefore, if the interface between the platform 32 and the application 31 is made common, the platform 32 absorbs the difference between the RTOS 33 and the hardware 34 for each ECU. Therefore, the same application 31 may be used for different types of ECUs. it can. That is, the application 31 can be rearranged.

  The programs in the ROM are divided into program units called tasks, and the CPU 13 executes one task at a time among the plurality of tasks. Then, the CPU 13 sequentially switches the tasks to be executed based on a predetermined priority order among tasks. This execution task switching function is called a task scheduling function. The task scheduling function is realized by the RTOS 33.

  FIG. 3 shows an example of the execution order of various tasks executed by the CPU 13. In this example, the CPU 13 executes a measurement task, a PF task 1, an AP task 1, 2,... N, a PF task 2, and the like. Each of these tasks is assigned a higher priority in this order. For example, when the execution timing 63 of the AP task 2 comes during the execution timing 53 of the PF task 2, which is an idle task executed when there is no other program to be executed, the CPU 13 ends the execution of the PF task 2, The execution of AP task 2 is started.

  The AP task (corresponding to an example of a first group task belonging to the first group) refers to a task that is a unit of an application program, and is a PF task (an example of a second group task belonging to the second group). Corresponds to a task that is a unit of the platform program. A measurement task having a higher priority than any PF task over any AP task is executed at a predetermined cycle Tc (for example, 1 ms) by a timer interrupt.

  Note that the function provided by the RTOS allows the CPU 13 to execute a task start hook function at the start of execution of each task and to execute the task end hook function at the end of each task. 4 and 5 are flowcharts showing the processing contents of the task start hook function 100 and the task end hook function 200, respectively.

  In the execution of the task start hook function 100, the CPU 13 first acquires the task ID of the task to be started in step 110. The task ID is a code assigned to each task in advance (at the time of design) in order to identify each task. Based on the content of this task ID, it can be determined whether the corresponding task is an AP task or a PF task. Since the task ID acquisition method is well known, the details thereof will not be described here.

  In step 120, it is determined whether the acquired task ID indicates a PF task or an AP task. If it is determined that the PF task is indicated, then in step 130, the current time is acquired based on the output signal from the timer 10, the current time is recorded in the RAM 11 as the variable Spf, and then the task start hook function 100 execution is terminated.

  If it is determined in step 120 that an AP task is indicated, then in step 140, the task that has started execution (hereinafter referred to as an execution task) is designated as a task whose execution time is to be measured (hereinafter referred to as a specified task). It is determined whether or not. Specifically, this determination is made by assigning the task ID acquired in step 110 to one of one or a plurality of designated task IDs recorded in advance in the RAM 11, ROM 12, non-illustrated nonvolatile writable storage medium, or the like. It depends on whether you are doing it. The designated task ID may be recorded in the RAM 11 as needed by an operator using an external device such as the RAM monitor 2.

  If the execution task is not one of the designated tasks, the execution of the task start hook function 100 is terminated. If it is one of the designated tasks, then in step 150, the current time is obtained based on the output signal from the timer 10 Then, the current time is recorded in the RAM 11 as a variable Sapp, and then the execution of the task start hook function 100 is terminated.

  As described above, when the task is started, if the task is a PF task or a designated task, the CPU 13 sets the start time as the AP task execution start time or the PF task execution start time. To record.

  In executing the task end hook function 200, the CPU 13 first acquires the task ID of the task to be ended in step 210. In step 220, it is determined whether the acquired task ID indicates a PF task or an AP task. If it is determined that the acquired task ID indicates a PF task, then step 230 is executed to indicate the AP task. If it is determined that there is, then step 250 is executed.

  In step 230, the current time E is acquired from the timer 10, and in step 240, the result of subtracting the value of the variable Spf from the current time E is added to the value of the variable Tpf. The result of subtracting the value of the variable Spf from the current time E is the time from the start of the task whose execution is to be ended to the present (ie, at the end of execution). In other words, this subtraction value is the execution time of the current execution task. The variable Tpf is reset to zero when the measurement task is executed, as will be described later. Therefore, the variable Tpf represents the total execution time of the PF task from the last execution of the measurement task to the present. After step 240, execution of the task end hook function 200 ends.

  In step 250, it is determined whether or not the task to be terminated is one of the designated tasks. If it is not one of the designated tasks, the execution of the task termination hook function 200 is terminated. Then, step 260 is executed. In step 260, the current time E is obtained from the timer 10, and then in step 270, the value obtained by subtracting the value of the variable Sapp from the current time E is added to the value of the variable Tapp. The result of subtracting the value of the variable Sapp from the current time E is the time from the start of the task whose execution is to be ended to the present (that is, at the end of execution). In other words, this subtraction value is the execution time of the current execution task. The variable Tapp is reset to zero when the measurement task is executed, as will be described later. Therefore, the variable Tapp represents the total execution time of all designated tasks from the last execution of the measurement task to the present. After step 270, execution of the task end hook function 200 ends.

  In this way, at the end of execution of the task, if the task is a PF task or a designated task, the CPU 13 determines the difference between the end time and the execution start time of the task recorded in the RAM 11. The current execution time of the task is specified, and the specified execution time is added to the variable Tpf or the variable Tapp. As a result, immediately before the execution timing of the next measurement task, the total execution time of all the PF tasks executed during the period Tc is recorded in the variable Tpf, and the variable Tapp includes the period The total execution time of all designated AP tasks executed during Tc is recorded. For example, in FIG. 3, when AP task 1 and AP task n are designated tasks, the sum of the execution times 61, 65, 66 is the total of the designated tasks in the period Tc from the measurement task execution timings 41 to 42. The execution time Tapp is set, and the sum of the execution times 62 and 67 is the total execution time Tapp of the designated task in the period Tc from the execution timing 42 to 43 of the measurement task.

  Here, the details of the measurement task will be described. FIG. 6 shows a flowchart of the measurement task 300. In the execution of the measurement task 300, the CPU 13 first determines in step 310 whether to calculate the CPU usage time by the designated AP task or to calculate the CPU usage time by all AP tasks.

  This determination is executed based on a setting value recorded in advance in the RAM 11, the ROM 12, or a writable nonvolatile storage medium (not shown). Here, the set value may be determined at the time of manufacture of the ECU 1, or may be recorded in the RAM 11 as needed by an operator using an external device such as the RAM monitor 2.

  When calculating the CPU usage time by all AP tasks, subsequently, in step 320, the average value of the variable Tpf and the variable Tpf ′ is substituted into the variable Tpf_ave. Here, as will be described later, Tpf ′ is the total execution time of the PF task executed between the last time and the execution timing of the previous measurement task 300. Since the variable Tpf is the total execution time of the PF task executed from this time to the execution timing of the previous measurement task 300, the variable Tpf_ave is the total execution time of the PF task in the two most recent consecutive periods Tc. Is the average value. This process is a kind of filtering process for the total execution time that changes every period Tc.

  In step 330, the result of subtracting the variable Tpf_ave from the period Tc is substituted into the variable Upf. The value of this variable Upf is the time during which the PF task is not executed within the period Tc. In this embodiment, the PF2 task is always executed when no other task is executed. Therefore, the time when the PF task is not executed is the same as the time when a task other than the PF task is executed. . Therefore, the variable Upf is the total execution time within the period Tc of substantially all AP tasks.

  Subsequently, as a process for the next period Tc, the current Tpf value is substituted into the variable Tpf ′ at step 340, and Tpf is reset to zero at step 350. In this way, in the next measurement task 300, the variable Tpf ′ is used as the total execution time of the PF task in the period Tc immediately before the measurement task 300 is executed. After step 350, execution of the measurement task 300 ends. Through the processing in steps 320 to 350 as described above, the average of the execution times of all AP tasks in the two most recent periods Tc can be calculated. Then, by dividing this execution time by the period Tc, it is possible to specify the CPU utilization rate by all AP tasks in the two most recent periods Tc.

  When calculating the CPU usage time by only the designated AP task, in step 360, the average value of the variable Tapp and the variable Tap 'is substituted for the variable Tap_ave. Here, Tap 'is the total execution time of the designated AP task executed between the previous time and the execution timing of the previous measurement task 300, as will be described later. Since the variable Tapp is the total execution time of the designated AP task executed from this time to the execution timing of the previous measurement task 300, the variable Tap_ave is the total of the designated AP tasks in the two most recent consecutive periods Tc. Execution time. This process is a kind of filtering process for the total execution time that changes every period Tc.

  Subsequently, as a process for the next period Tc, the value of the current variable Tapp is substituted into the variable Tapp ′ at Step 370, and the variable Tapp is reset to zero at Step 380. As a result, in the next measurement task 300, the variable Tapp ′ is used as the total execution time of the PF task in the period Tc immediately before the measurement task 300 is executed. After step 380, execution of measurement task 300 ends. Through the processes in steps 360 to 380, the average of the execution times of all AP tasks in the two most recent periods Tc can be calculated. Then, by dividing this execution time by the period Tc, it is possible to specify the CPU utilization rate by all the designated AP tasks in the two most recent periods Tc.

  As described above, for each task, the execution time of the task can be specified by specifying the difference between the start time and the end time of the task as the execution time. By using such a method, even if the task execution time is very short, the execution time can be reliably specified, and it can be determined by other processes executed as part of the idle task. There is no error in the calculation of execution time.

  In this way, the task ID of the AP task designated in advance is collated with the task ID of the AP task to start execution, and when they match, the difference between the start time and end time of the AP task is executed. By recording the time, the execution time of the desired task can be specified.

  Further, the total execution time of all AP tasks or all designated AP tasks calculated for each period Tc is subjected to a filtering process using calculation results in a plurality of periods Tc in the past. When the filtering process is not performed, as shown in FIG. 7, since the variation of the calculated values 71 to 76 is large between the different periods Tc, the waveform 77 created based on the calculated values 71 to 76 is displayed. The shape is also changing drastically.

  However, when filtering is performed, as shown in FIG. 8, variations in the calculated values 81 to 86 between the different periods Tc are suppressed, so that the waveform 77 created based on the calculated values 81 to 86 is used. The shape of the change is slow. Therefore, when the data obtained as a result of filtering is acquired by using the RAM monitor 2, the operator does not need to perform work such as averaging of the calculation results again.

  Further, since the measurement task is realized as a platform task, the designer of the application task does not need to create a program for calculating the execution time of the application task. Therefore, the task processing load can be measured regardless of the design contents of the application.

  In the above embodiment, the ECU 1 corresponds to an example of an electronic computer, and the RAM 11, the ROM 12, and the registers in the CPU 13 correspond to an example of a storage medium. The CPU 13 functions as an example of a determination unit by executing step 140 of the task start hook function 100, and functions as an example of a start time recording unit by executing step 150. Executing 270 functions as an example of an end time recording unit, and executing step 130 of the task start hook function 100 and step 240 of the task end hook function 200 functions as an example of a start / end time calculating unit. By executing steps 320, 33, 340, and 350 of the measurement task 300, it functions as an example of a measurement result recording unit.

(Other embodiments)
As mentioned above, although embodiment of this invention was described, the scope of the present invention is not limited only to the said embodiment, The various form which can implement | achieve the function of each invention specific matter of this invention is included. It is.

  For example, in the above-described embodiment, the ECU 1 is an ECU mounted on the vehicle, but the electronic calculation device of the present invention may not be mounted on the vehicle.

  In the embodiment described above, the execution time of the measurement task may be included in the total execution time of the PF task, or may not be included. Since the execution time of the measurement task in the period TC is sufficiently shorter than that in the period TC, in either case, the measurement of the execution time of the application task is not greatly affected.

  Further, the priority relationship between the AP task and the PF task is not limited to that shown in FIG. 3 and may be any method.

1 is a block diagram showing a configuration of an ECU 1 and a connection relationship with a RAM monitor 2 according to an embodiment of the present invention. It is a figure which shows the hierarchical division of the software which CPU13 performs. It is a timing diagram which shows an example of the execution order of the various tasks in CPU13. 4 is a flowchart of a task start hook function 100. 5 is a flowchart of a task end hook function 200. 5 is a flowchart of a measurement task 300. It is a figure which shows the change waveform 77 of the total execution time when filtering is not performed. It is a figure which shows the change waveform 77 of the total execution time in case filtering is performed.

Explanation of symbols

1 ... ECU, 2 ... RAM monitor, 10 ... timer, 11 ... RAM, 12 ... ROM,
13 ... CPU, 31 ... application, 32 ... platform, 33 ... RTOS,
34 ... Hardware, 41-43 ... Measurement task, 51-55 ... PF task,
61-67 ... AP task, 71-76, 81-86 ... calculated value, 77, 87 ... waveform,
100: Task start hook function, 200: Task end hook function,
300: Measurement task.

Claims (6)

An electronic computing device comprising a storage medium and a CPU, and switching a task to be executed by the CPU from a plurality of tasks recorded in the storage medium,
The CPU is:
Determining means (140) for determining whether or not the execution task is a designated task recorded in the storage medium when starting execution of one of the plurality of tasks (hereinafter referred to as an execution task); ,
When the execution result of the execution task is started based on the determination result of the first determination means being positive, the start time is recorded in the storage medium as the execution start time of the execution task. Recording means (150);
At the end of execution of the execution task, a recording at the end of recording the difference between the time at the end of the execution task and the execution start time of the execution task recorded on the storage medium as the execution time of the execution task Means (270);
An electronic computing device characterized by comprising: A CPU having a storage medium and a CPU, and executed by the CPU from among a plurality of first group tasks belonging to a first group and a plurality of second group tasks belonging to a second group recorded in the storage medium An electronic computing device for switching a target task,
The CPU always executes one of the plurality of second group tasks when none of the plurality of first group tasks is executed,
The CPU is:
In each execution of the second group task within a predetermined measurement period, when the execution of the second group task (hereinafter referred to as an execution task) to be executed starts, the time at the start is used to start the execution of the execution task. The time is recorded in the storage medium, and at the end of execution of the execution task, the difference between the end time and the execution start time of the execution task recorded in the storage medium is Start / end time calculating means for calculating as execution time;
The result obtained by subtracting the total execution time of the execution tasks calculated by the start / end time calculation means within the measurement period from the measurement period is recorded in the storage medium as the execution time of the plurality of first group tasks. A measurement result recording means;
An electronic computing device comprising: Each of the tasks belonging to the second group is a platform task for directly controlling the hardware and operating system of the electronic computing device, and each of the tasks belonging to the first group is a hardware task of the electronic computing device. The electronic computing device according to claim 2, wherein the electronic computing device is an application task that uses a hardware and an operating system via the platform task. The electronic calculation apparatus according to claim 3, wherein the measurement result recording unit belongs to the platform task. A program comprising a storage medium and a CPU, and used for an electronic computing device that switches a task to be executed by the CPU from a plurality of tasks recorded on the storage medium,
Determining means for determining whether or not the execution task is a designated task recorded in the storage medium when starting execution of one of the plurality of tasks (hereinafter referred to as an execution task);
When the execution result of the execution task starts based on the determination result of the first determination means being affirmative, the start time is recorded in the storage medium as the execution start time of the execution task. Recording means, and
At the end of execution of the execution task, a recording at the end of recording the difference between the time at the end of the execution task and the execution start time of the execution task recorded on the storage medium as the execution time of the execution task As a means, a program for causing the CPU to function. A CPU having a storage medium and a CPU, and executed by the CPU from among a plurality of first group tasks belonging to a first group and a plurality of second group tasks belonging to a second group recorded in the storage medium A program used for an electronic computing device that switches a target task and causes the CPU to execute any one of the plurality of second group tasks whenever any of the plurality of first group tasks is not executed. ,
In each execution of the second group task within a predetermined measurement period, when the execution of the second group task (hereinafter referred to as an execution task) to be executed starts, the time at the start is used to start the execution of the execution task. The time is recorded in the storage medium, and at the end of execution of the execution task, the difference between the end time and the execution start time of the execution task recorded in the storage medium is Start / end time calculating means for calculating the execution time; and
The result obtained by subtracting the total execution time of the execution tasks calculated by the start / end time calculation means within the measurement period from the measurement period is recorded in the storage medium as the execution time of the plurality of first group tasks. A program that causes the CPU to function as measurement result recording means.

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